[Bug target/85095] [6/7/8 Regression] worse code generated

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85095

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |jakub at gcc dot gnu.org

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 43778
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=43778&action=edit
gcc8-pr85095.patch

Untested fix.  What happens is that combine uses simplify-rtx.c which optimizes
away the useless outer (plus with const0_rtx), and we don't have a pattern that
matches that.